Mineralization reactions will be studied under highly reproducible conditions by the addition of well-characterized seed material to stable supersaturated solutions of calcium phosphate at the physiological pH. Reactions will be followed by monitoring the ionic concentrations in the supersaturated solutions and by examination of the solid phases using x-ray diffraction, infrared and specific surface area measurements and by optical and scanning electron microscopy. The technique enables studies to be made not only of the kinetic of mineralization but also of the effects of inhibitors, such as the fluorides and phosphonates, which are known to be effective in controlling caries. Mineralization studies will also be made using the organic component of dentine and cementum and parallel histological cross-sectioning studies will be made in order to identify the sites of mineralization. The kinetics of demineralization of dental enamel, both sound and white spot, is being investigated using a theoretically sound rotating disc technique.